Treating hydrocarbons



Patented July 13, 1943 UNITED STATES PATENT OFFICE TREATING HYDROCARBONS Peter J. Gaylor, Union, and Edward J. Mahler, Jersey City, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application December 12, 1940, Serial No. 369,758

3 Claims.

number thereof, and many commercial gasolines,

contain substantial quantities of this hydrocarbon. However, the amount of benzene available in this country is too limited to permit its full use as a blending agent in gasoline. That is to say, while it would be desirable to market commercial gasolines containing about 40% to 50% benzene, the total national benzene production is too low to permit its use to, this extent.

A number of methods for producing benzene from petroleum raw materials have been developed by prior art processes, but none of these processes is able to manufacture this aromatic hydrocarbon at a price competitive with that of the coal tar product. Since petroleum is available in this country in large quantities, an inexpensive and efficient process making it possible to produce large quantities of benzene from petroleum derivatives would have considerable value. Of course, in addition to its uses in the manufacture of motor fuels, benzene enjoys a large number of other commercial uses. Cyclohexane likewise finds wide commercial uses in the fuel, solvent and other fields.

The main object of the invention is to produce cyclohexane and/or benzene and/or alkyl derivatives thereof from lower mono-olefins of .less than five carbon atoms. When lower olefins are polymerized catalytically, according to present practice, good yields of liquid products are obtained, but these products contain only substantially olefin polymers and no aromatics. On the other hand, high temperature non-catalytic polymerization does result in the formation of some cyclic hydrocarbons, but this is accompanied by excessive formation of methane and other low molecular weight by-products which seriously afiect the cyclic hydrocarbon yield, making the process uneconomical.

According to the present invention, a catalytic method may be employed to obtain cyclic hydrocarbons directly in high yields and without substantial loss in waste lay-product gases.

According to the present invention, a lower olefin, preferably of 3-4 carbon atoms, may be made to undergo, by catalytic directing influence, a direct cyclo-polymerization in accordance with an overall mechanism which may be illustrated by the following equations:

CQHQ 3H: Benzene 0.115013; Toluene C eHn C H: Methyl cyclohcxane The process involves the use of a mixed catalyst comprising a volatile halide of the Friedel- CaHo C4Ha 2 CsHu C4Ha Crafts type, e. g.-AlCl3, BFa, HgClz, etc., and a cyclizing metal or metal compound, e. g., compounds of Mo, W, Al, V, U, Cr, Cu, Ni, etc. Examples of such latter cyclizing compounds are molybdenum sulfide or oxide, chromic oxide or sesquioxide, aluminum oxide or fluoride, tin oxide, copper, etc. Combinations of the latter are preferable, and as examples, the following have been found suitable: aluminum fluorideni'ckel, molybdenum sulfide-copper, aluminasilica-tin oxide, alumina-chromium oxide, alumina-nickel, chromium oxide-tungsten oxide alumina, and the like.

It is preferable that the volatile inorganic halide be added to the olefin feed stock in amounts of 0.3-2% by weight of the charge, more or less, prior to contacting with the substantially non-volatile, solid cyclizing catalyst. It is also desirable that the reactants be substantially in the anhydrous condition, since small amounts of moisture have been found to gradually inactivate the solid catalyst mass. However, hydrogen may be added to the reacting mixture and in many cases, e. g., with the chromium combination catalysts, its use is desirable to suppress carbon formation on the catalyst surface.

The reaction temperature and pressure depend more or less upon the pe of cyclic product desired. If cyclohexane or its derivatives are to be produced, the temperature is preferably low, below about 200 (3., and preferably. below C. but above about room temperature, and the pressure is at least that suificient to maintain a liquid reaction phase. For example, in the case of propene, as a raw material, the pressure should preferably be above about 100 lbs/sq. in. and up to about 1000 lbs/sq. in, although pressures up to about 5000 lbs. or even higher may be employed. With butene, the pressure is preferably above 30 lbs/sq. in.

If benzene or its derivatives are desired, it is preferable to operate at substantially atmospheric pressure and higher temperatures, say 200-350 C. and possibly higher, this, oi course, depending on the rate of flow of the reactant over the catalyst, the higher rate requiring a 'higher temperature for satisfactory conversion.

It is possible to prepare cyclohexane or its derivatives by the process previously outlined and then to dehydrogenate the product in a separate step to benzene or its derivatives in the presence of dehydrogenating catalysts at about 300-500 C.

The olefinic materials to be employed are the aliphatic olefins of three or four carbon atoms, alone, or in admixture with each other. Ethylene may be added, but preferably not over amounts in excess of equimolecular quantities necessary to produce six carbon ring compounds with the heavier olefins by cyclo-copolymerization.

Alkylation of the aromatic products by means of the olefin feed stock may be suppressed by the introduction of small amounts of sulfur or sulfur compound such as sulfur dioxide, or any other condensation inhibitor. These, of course, cannot be employed with catalysts such as nickel or copper which are readily poisoned by such materials. Condensation reactions can be suppressed to a minimum, however, by adjusting temperature and time conditions so as to remove the aromatics as soon as they are formed followed by rapid hydrolysis of the halide catalyst by introduction of steam, water, alcohol, and the like to the stream immediately after leaving the actor.

In order to illustrate the present invention, the following specific examples are set forth, with the understanding that the precise details enumerated therein are purely illustrative and do not impose a limitation on our invention.

Example 1 Substantially anhydrous liquid propylene is placed in a bomb provided with a stirrer and a finely divided mixture of nickel and aluminum fluoride is added in an amount of about 2% by weight of the charge. The bomb is heated to about 100 F. (the pressure being about 190 lbs.) and boron fluoride is gradually bled into the bomb. The reaction is exothermic and overheating must be avoided. After 0.5% BF; (based on the weight of the charge) has been added, the contents are cooled, washed with water or alcohol, (after filtering out the cyclizing catalyst) and the cyclohexane recovered by distillation.

Example 2 Substantially anhydrous propylene is admixed with 0.3% BFr. and immediately passed into a tube containing a molybdenum sulfide-cop er mixture maintained at 325 C. and atmospheric pressure. The rate is adjusted so that not more than 2% to 5% of the propylene is converted to lower hydrocarbons. The product is immediately quenched with water and the benzene and other 'cyclic hydrocarbons are separated by cooling the washed gases or by scrubbing with a heavy oil.

Example 3 Liquefied propylene is mixed with a small amount, about 1% to 2% by weight of finely divided nickel and about 0.3% BF: is gradually added to the mixture while stirring. The temperature in the reaction zone is maintained around 20 C., and the pressure prevailing within the reaction zone is about 150 lbs/sq. in. After four hours, the liquid mixture is filtered, sprayed through water to hydrolyze the BFa, and then fractionated, and the product boiling at -85 C. is passed'over a catalyst consisting of chromium oxide and alumina, at such a rate that the hydrocarbon is in contact with the catalyst for a period of time within the range of from about 1-30 seconds. The temperature conditions prevailing in this second stage are in the neighborhood of about 450" C. The products are then conducted to a fractionating column from which the aromatic constituents are removed.

Other materials which may be added to the reaction mixture are acetylene, carbonyls of chromium, molybdenum, nickel, and the like.

What we claim is:

1. Method for producing mono-cyclic hydro carbons comprising subjecting an aliphatic mono-olefin of 3 to 4 carbon atoms to the action of a volatile halide of the Friedel-Crafts type and a cycllzing catalyst comprising molybdenum sulfide and copper at a temperature between 20 C.

and 350 C.

2. The process of producing cyclic hydrocarbons from one 01' the class consisting of propylene and butylene which comprises admixing the olefin with a small amount of boron fluoride, passing the mixture into a zone containing a molybdenum sulfide-copper mixture, the said zone be ing maintained at a temperature of about C. and under a substantially atmospheric pressure, maintaining the reactant in the reaction zone for a period of from 1-30 seconds, thereafter quenching the reaction products and recovering cyclic hydrocarbons therefrom.

3. The process of producing cyclohexane compounds asset forth in claim 2, in which the temperature is from 20 C. to 200 0., and the pressure is greater than 30 lbs/square inch.

PETER J. GAYLOR. EDWARD J. MAKER. 

